Liquid skin cleanser

ABSTRACT

A skin cleansing composition comprising a salt of lauric acid; a salt of stearic acid; and at least one surfactant that is not a salt of a fatty acid; wherein the ratio of the salt of lauric acid to the salt of stearic acid, calculated as the ratio of lauric acid to stearic acid by weight, is from 2.5:1 to 3.5:1. Also provided are methods of using the compositions.

BACKGROUND

Liquid skin cleansers have become very popular with consumers over thelast twenty years. It is desirable for such skin cleansers to rinse ofeasily, and also leave the skin with a “squeaky-clean” feel.Consequently, there is a need for liquid skin cleansing compositionsthat are effective cleansers, and also leave the skin feeling clean.

BRIEF SUMMARY

The inventors have discovered that the combination of a salt of a shortchain fatty acid, for example lauric acid, together with a blend ofsalts of long chain fatty acids, for example a blend of palmitic andstearic acid, provides excellent sensory and performance properties whenformulated into a skin cleansing composition. Preferably, the ratio ofthe amount of short chain faty acid, to the amount of blend of longchain fatty acid is from 2.5:1 to 3.5:1. The compositions also possesssuperior antibacterial efficacy, allowing for use of a lower dosage ofantibacterial compound in the composition.

In a first exemplary embodiment, the present disclosure provides aliquid skin cleanser composition comprising:

-   a) a salt of lauric acid;-   b) a blend of salts of stearic acid and palmitic acid; and-   c) at least one surfactant that is not a salt of a fatty acid;    wherein the ratio of the salt of lauric acid to the blend of salts    of stearic acid and palmitic acid, calculated as the ratio by weight    of lauric acid to combined weight of stearic acid and palmitic acid,    is from 2.5:1 to 3.5:1. Optionally, the liquid skin cleanser    contains an antibacterial agent.

In further exemplary embodiments, the disclosure provides methods ofcleaning skin using the disclosed compositions, and methods for theirpreparation.

DETAILED DESCRIPTION

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. As used throughout, ranges are used as shorthandfor describing each and every value that is within the range. Any valuewithin the range can be selected as the terminus of the range.

As used herein, the term “liquid skin cleaning composition” shallinclude non-solid forms such as creams and gels, for cleansing andpersonal hygienic use comprising at least one cleanser chosen from soapand surfactant.

In one exemplary embodiment, the present disclosure provides a liquidskin cleanser composition (Composition 1) comprising:

-   a) a salt of lauric acid; and-   b) a blend of salts of stearic acid and palmitic acid; and-   c) at least one surfactant that is not a salt of a fatty acid;    wherein the ratio of the salt of lauric acid to the blend of salts    of stearic acid and palmitic acid, calculated as the ratio by weight    of lauric acid to combined weight of stearic acid and palmitic acid,    is from 2.5:1 to 3.5:1; for example:    -   1.1 Composition 1, wherein the ratio of the salt of lauric acid        to the combined salts of palmitic and stearic acids, calculated        as the ratio of weight of lauric acid to combined weight of        palmitic and stearic acid, is about 3:1.    -   1.2 Composition 1 or 1.1, wherein the ratio of the amount of        salt of palmitic acid to the amount of salt of stearic acid in        the blend, calculated as the ratio of weight of palmitic acid to        stearic acid in the blend is from 1.3:1 to 1.8:1; preferably        about 1.5:1.    -   1.3 Any preceding Composition 1 et seq., wherein the salts of        lauric acid, stearic acid and palmitic acid are alkali metal        (e.g., sodium or potassium) salts, triethanolamine salts,        ammonium salts, and combinations thereof.    -   1.4Any preceding Composition 1 et seq., wherein the salts of        lauric acid, stearic acid and palmitic acid are potassium salts.    -   1.5Any preceding Composition 1 et seq., which is devoid of        myristic acid or its salts.    -   1.6 Any preceding Composition 1 et seq., which is devoid of        salts of fatty acids other than the salts of lauric acid,        stearic acid and palmitic acid.    -   1.7 Any preceding Composition 1 et seq. further comprising an        antibacterial agent.    -   1.8 Composition 1.6, wherein the antibacterial agent is        trichlorocarbanilide, in an amount of from 0.01% to 0.15% by        weight of the composition, for example from 0.1% to 0.15% by        weight of the composition.    -   1.9 Composition 1.6 or 1.7, wherein the antibacterial agent is        trichlorocarbanilide, which is present in an amount of from        0.01% to 0.3% by weight of the composition.    -   1.10Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is selected        from anionic surfactants, amphoteric surfactants, zwitterionic        surfactants, and non-ionic surfactants.    -   1.11 Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is selected        from the group consisting of sodium or ammonium salts of alkyl        ether sulfates, sodium laureth sulfate, and combinations        thereof.    -   1.12 Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is sodium        laureth sulfate, which is present in the composition an amount        of from 5% to 12% by weight; for example about 8% by weight.    -   1.13Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is an        ethoxylated fatty alcohol.    -   1.14Any preceding Composition 1 et seq., wherein the ethoxylated        fatty alcohol is present in the composition an amount of from        0.2% to 1% by weight; optionally about 0.6% by weight.    -   1.15Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is a        propoxylated monoethanolamide.    -   1.16 Composition 1.14, wherein the propoxylated monoethanolamide        is PPG-2 Hydroxyethyl Cocamide, which is present in the        composition an amount of from 0.2% to 1% by weight; optionally        about 0.6% by weight.    -   1.17Any preceding Composition 1 et seq., wherein the at least        one surfactant that is not a salt of a fatty acid is        cocoamidopropyl betaine.    -   1.18Composition 1.16, wherein the cocoamidopropyl betaine is        present in an amount of 5% to 12% of the composition by weight,        optionally 8% to 9% of the composition by weight.    -   1.19Any preceding Composition 1 et seq., further comprising        cocomonoethanolamide in an amount of from 0.5% to 2.5% of the        composition by weight, for example about 1.5% of the composition        by weight.    -   1.20Any preceding Composition 1 et seq., wherein the composition        comprises        -   a) potassium laurate,        -   b) potassium stearate,        -   c) potassium palmitate,        -   d) sodium laureth sulfate,        -   e) cocoamidopropyl betaine,        -   f) ethoxylated fatty alcohol, and        -   g) cocomonoethanolamide.    -   1.21Any preceding Composition 1 et seq., wherein the composition        comprises:        -   a) 4 to 6% by weight of the potassium laurate,        -   b) 1 to 2% by weight of the potassium stearate,        -   c) 0.8 to 2% by weight of the potassium palmitate,        -   d) 8 to 13% by weight of the sodium laureth sulfate,        -   e) 5 to 9% by weight of the cocoamidopropyl betaine,        -   f) 0.6 to 1.2% by weight of the ethoxylated fatty alcohol,            and        -   g) 0.5 to 2% by weight of the cocomonoethanolamide.

The liquid skin cleanser compositions of the invention comprise a metalsalt of lauric acid, and metal salts of a blend of palmitic and stearicacids. Preferably, the metal salts are alkali metal salts, e.g., sodiumor potassium salts. In some preferred embodiments, the salts arepotassium salts.

The inventors have discovered that the combination of a salt of a shortchain fatty acid, for example lauric acid, together with a blend ofsalts of long chain fatty acids, for example a blend of palmitic andstearic acid, provides excellent sensory and performance properties whenformulated into a skin cleansing composition. Preferably, thecompositions comprise a ratio of the amount of short chain fatty acid,to the amount of blend of long chain fatty acid, of from 2.5:1 to 3.5:1,calculated as the weight of the acid. The blend of long chain fattyacids contains, in some preferred embodiments, a ratio of amount ofpalmitic acid to amount of stearic acid by weight of from 1.3:1 to1.8:1; preferably about 1.5:1. For example, in some preferredembodiments, the compositions of the invention comprise a blend of 40%by weight stearic acid and 60% by weight palmitic acid, together with anamount of lauric acid, such that the ratio of the weights of lauric acidrelative to combined weights of palmitic and stearic acid, is from 2.5:1to 3.5:1, preferably about 3:1.

The compositions also possess superior antibacterial efficacy, allowingfor use of a lower dosage of antibacterial compound in the composition.

While not wishing to be bound by particular theory, it is believed thatdifferences in carbon chains of fatty acid soaps affect attributes likeskin feel, ease of rinse off, lathering, and formula thickeningproperties. In particular, Applicants have discovered that that longchain fatty acid soaps, for example those having eighteen or carbonatoms, are key contributors to producing a squeaky skin feel, which isattractive to many consumers. Thus, in some embodiments, thecompositions do not contain myristic, or its salts. In some embodiments,the compositions are devoid of salts of fatty acids other than the saltsof lauryl acid, palmitic acid and stearic acid.

The lauric acid and palmitic/stearic acid salts can be added directly tothe formulation, or they can be created in situ from their parent acids.For example, the desired amount of lauric acid and blend of palmitic andstearic acids can be added to the formulation, and the pH adjusted, forexample by addition of an aqueous hydroxide such as potassium hydroxide,to form the solubilized salts. Thus, as used herein, the ratio of thesalt of lauric acid to the salts of stearic acid and palmitic acid,calculated as the ratio of lauric acid to palmitic and stearic acid byweight, is intended to mean the relative amounts of salts of lauricacid, palmitic acid and stearic acid produced by adding the indicatedratio of the corresponding acids.

The compositions optionally contain an antibacterial agent. Suitableantibacterial agents for the compositions of the invention include, butare not limited to, trichlorocarbanilide, triclocarban,PCMX/chloroxylenol, IPMP/o-Cymen-5-ol, Zinc Compounds, andPhenoxyethanol. Typically, the antibacterial agent is present in anamount of from 0.01% to 0.75%, for example from 0.01% to 0.3 by weightof the composition. In some preferred embodiments, the compositionsinclude trichlorocarbanilide in an amount of from 0.01% to 0.3% byweight of the composition, preferably about 0.1% by weight of thecomposition.

The compositions disclosed herein also contain, in addition to theaforementioned lauric, palmitic and stearic acid salts, at least onesurfactant that is not a fatty acid or a salt of a fatty acid. Incertain embodiments, the surfactant is at least one of an anionicsurfactant, an amphoteric surfactant, a zwitterionic surfactant, and anon-ionic surfactant. In some embodiments, the surfactant is an anionicsurfactant, for example a sulfate, sulfonate alpha olefin sulfonate,isethionate such as SCI, N-alkyl or N-acyl taurate, sulfosuccinate, orphosphate. In some embodiments, the surfactant is sodium laureth sulfate(SLES), preferably in an amount of from 5% to 12% of the composition byweight, for example about 8% of the composition by weight.

The compositions disclosed herein can also contain one or more nonionicsurfactants, for example and not limited to propoxylatedmonoethanolamides such as PPG-2 Hydroxyethyl Cocamide (Promidium CO),alkanolamides, alkylpolyglycosides which each can be present in thecomposition in an amount of from 0.2% to 1% by weight; for example about0.6% by weight.

In some embodiments, the compositions comprise cocoamidopropyl betainein an amount of from 5% to 12% of the composition by weight, for examplefrom 8% to 9% of the composition by weight.

In some embodiments, the compositions comprise cocomonoethanolamide inan amount of from 0.5% to 2.5% of the composition by weight, for exampleabout 1.5% of the composition by weight. In some embodiments, thecompositions comprise both cocoamidopropyl betaine andcocomonoethanolamide in the amounts stated above.

The compositions disclosed herein can also contain one or morepreservatives, for example and not limited to isothiazolinones such asmethylchloroisothiazolinone, alone or in combination withmethylisothiazolinone (e.g., Kathon™ CG), parabens (such aspropylparaben, ethylparaben and methylparaben), benzalkonium chloride,2-bromo-2-nitropropane-1,3-diol, Germaben H, a product of SuttonLaboratories, Inc., which comprises propylene glycol 50%, diazolidinylurea 30%, methylparaben 11%, and propylparaben 3%, hydantoins,imidazolines and BHT.

The compositions disclosed herein can also contain one or more chelatingagents, which can possess both preservative and antibacterialfunctionality, sequestering metals that bacteria require in order togrow. Suitable chelating agents include tetrasodium EDTA, pentetic acid,and pentasodium pentetate. One preferred chelating agent is tetrasodiumEDTA.

The compositions disclosed herein can also contain one or more alphahydroxy acids, for example citric acid. Such alpha hydroxy acids areknown to be useful for adjust the pH balance of the composition, andalso for promoting skin peeling and re-growth.

The compositions of this invention also may contain minor amounts ofconventional additional components, to impart any desiredcharacteristic, which are compatible with the skin cleanser formulation,and do not adversely affect its properties. Suitable additives include,but are not limited to, fragrances, colorants, skin conditioning agents,moisturizing agents, dyes and pigments, titanium dioxide, sunscreenactive ingredients such as butyl methoxy benzoylmethane; antiagingcompounds such as alpha hydroxy acids, beta hydroxy acids; polyols suchas glycerol, sorbitol, propylene glycol and polyethylene glycols;particulate matter such as silica, talc, or calcium carbonate;antioxidants such as butylated hydroxytoluene (BHT); vitamins such as A,E, K and C; essential oils and extracts thereof such as rosewood andjojoba, particulate matter such as polyethylene beads, jojoba beads,lufa, or oat flour, and mixtures of any of the foregoing components.

It will be recognized that individual components of the disclosedcompositions may possess multiple functionalities.

In a further embodiment, the present disclosure also provides a methodof cleaning skin comprising contacting the skin with any of Compositions1-1.20.

In a further embodiment, use of a metal salt of lauric acid and a blendof metal salts of palmitic acid and stearic acid in a liquid skincleanser that contains at least one surfactant that is not a salt of afatty acid for providing a squeaky clean feeling on skin after cleansing(Use 1).

-   1.1 Use 1, wherein the liquid skin cleanser is devoid of myristic    acid or its salts.-   1.2 Use 1 or 1.1, wherein the liquid skin cleanser is devoid of    salts of fatty acids other than the metal salts of lauric acid,    palmitic acid and stearic acid.

The liquid skin cleanser composition of the present disclosure may beprepared by any of the techniques known to those skilled in the art,including both batch processes and continuous processes.

EXAMPLES

Exemplary embodiments of the present disclosure will be illustrated byreference to the following examples, which are included to exemplify,but not to limit the scope of the present invention.

In the examples and elsewhere in the description of the invention,chemical symbols and terminology have their usual and customarymeanings. Temperatures are in degrees Celsius unless otherwiseindicated. The amounts of the components are in weight percents based onthe standard described; if no other standard is described then the totalweight of the composition is to be inferred. Various names of chemicalcomponents include those listed in the CTFA International CosmeticIngredient Dictionary (Cosmetics, Toiletry and Fragrance Association,Inc., 7^(th) ed. 1997).

Example 1

Table 1 shows the composition of a formulation according to theinvention and a comparative formulation containing myristic acid and afatty acid blend.

TABLE 1 Exemplary Composition of the Invention Comparative InventiveIngredient Weight % Weight % Demineralized Water and Q.S. Q.S. minors(antibacterial agent, preservative, pH adjustment, fragrance, etc.) SLES70% 8 8 Cocoamidopropyl 8.45 8.45 Betaine Cocomonoethanolamide 0 1.5 47%Potassium 4.2 4 Hydroxide soln. Lauric Acid 4.3 5.5 C12-18 Fatty acidblend 2.1 0 Myristic Acid 1.7 0 Blend of 40 wt. % Stearic 0 1.8 Acid and60 wt. % Palmitic Acid Ethoxylated alcohol 0.9 0.6 PPG-2 Hydroxyethyl0.9 0.6 Cocamide Potassium chloride 2 1.3

The compositions were used by panelists and rated on a scale of 1 to 10for squeaky clean feel. The compositions had parity performance, but theinventive composition had a lower cost based on the combination of thelauric acid and stearic acid salts.

Example 2 Foam Profile

An in-vitro laboratory foam profile was conducted. The results showedthat the inventive composition of Table 1 had significant improvementobserved in foam generation relative to the comparative formulation dueto the balance of fatty acids ratio. The results are in Table 2 below.

Comparative Inventive Formulation Time (s) Volume (ml) Volume (ml) 0 0 010 117 141 20 173 211 30 220 274 40 259 316 50 287 346 60 303 367 70 315389 80 324 411 90 339 427 100 348 446

What is claimed is:
 1. A liquid skin cleanser composition comprising: asalt of lauric acid; a blend of salts of stearic acid and palmitic acid;at least one surfactant that is not a salt of a fatty acid; andcocomonoethanolamide; wherein the ratio of the salt of lauric acid tothe blend of salts of stearic acid and palmitic acid, calculated as theratio by weight of lauric acid to combined weight of stearic acid andpalmitic acid, is from 2.5:1 to 3.5:1; wherein the salt of lauric acidis potassium laurate; the blend of salts of stearic acid and palmiticacid is a blend of potassium stearate and potassium palmitate; the atleast one surfactant that is not a salt of a fatty acid includes sodiumlaureth sulfate, cocoamidopropyl betaine, and ethoxylated fatty alcohol.2. The composition of claim 1, wherein the ratio of the salt of lauricacid to the combined salts of palmitic and stearic acids, calculated asthe ratio of weight of lauric acid to combined weight of palmitic andstearic acid, is about 3:1.
 3. The composition of claim 1, wherein theratio of the amount of salt of palmitic acid to the amount of salt ofstearic acid in the blend, calculated as the ratio of weight of palmiticacid to stearic acid in the blend is from 1.3:1 to 1.8:1; preferablyabout 1.5:1.
 4. The composition of claim 1, which is devoid of myristicacid, or its salts.
 5. The composition of claim 1, which is devoid ofsalts of fatty acids other than the salts of lauric acid, palmitic acidand stearic acid.
 6. The composition of claim 1 further comprising anantibacterial agent.
 7. The composition of claim 6, wherein theantibacterial agent is selected from trichlorocarbanilide, triclocarban,PCMX/chloroxylenol, IPMP/o-Cymen-5-ol, Zinc Compounds, andPhenoxyethanol, wherein the antibacterial agent is present in an amountof from 0.01% to 3% by weight of the composition.
 8. The composition ofclaim 6, wherein the antibacterial agent is trichlorocarbanilide, whichis present in an amount of from 0.01% to 0.3% by weight of thecomposition.
 9. The composition of claim 1, wherein sodium laurethsulfate is present in the composition an amount of from 5% to 12% byweight.
 10. The composition of claim 1, wherein the ethoxylated fattyalcohol is present in the composition an amount of from 0.2% to 1% byweight.
 11. The composition of claim 1, wherein the at least onesurfactant that is not a salt of a fatty acid further comprises apropoxylated monoethanolamide, wherein the propoxylated monoethanolamideis PPG-2 Hydroxyethyl Cocamide, which is present in the composition anamount of from 0.2% to 1% by weight.
 12. The composition of claim 1,wherein the cocoamidopropyl betaine is present in an amount of 5% to 12%of the composition by weight.
 13. The composition of claim 1, whereincocomonoethanolamide is present in an amount of from 0.5% to 2.5% of thecomposition by weight.
 14. The composition of claim 1, wherein thecomposition comprises: 4 to 6% by weight of the potassium laurate, 1 to2% by weight of the potassium stearate, 0.8 to 2% by weight of thepotassium palmitate, 8 to 13% by weight of the sodium laureth sulfate, 5to 9% by weight of the cocoamidopropyl betaine, 0.6 to 1.2% by weight ofthe ethoxylated fatty alcohol, and 0.5 to 2% by weight of thecocomonoethanolamide.